Mobiles

#include <iostream>
using namespace std;
int t[100001][2];
int k, l, n, x=0, c=0, d=0, e=0, y=0;
void f(int a, int b){
	if (a==-1) {
		if (b!=c && b!=d){
			if (c==0) c=b;
			else if (d==0 && (c==b+1 || c==b-1)) d=b;
			else e=1;
		}
	}
	else {
		f(t[a][0], b+1);
		f(t[a][1], b+1);
	}
}
int g(int a){
	if (a==-1) return 1;
	t[a][0]=g(t[a][0]);
	t[a][1]=g(t[a][1]);
	if (t[a][0]<t[a][1]) y++;
	return t[a][0]+t[a][1];
}
int main(){
	cin >> n;
	for (int i=1; i<=n; ++i) {
		cin >> k >> l;
		t[i][0]=k;
		t[i][1]=l;
		if ((k==-1 && l!=-1) || (k!=-1 && l==-1) ) x++;
	}
	f(1, 1);
	g(1);
	if (e || x>1) cout << "-1\n";
	else cout << y << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: WRONG ANSWER

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED

Test 41

Verdict: ACCEPTED

Test 42

Verdict: ACCEPTED